The invention relates to a pressure connection device for a guidewire unit that is operated with a pressure medium. Such guidewire units are used, in particular, for medical instruments, as for example catheters in body ducts and/or tissue channels of a patient.
WO 2004/035124 A1 discloses a guidewire unit, which can be stiffened in a controlled manner and which can be put selectively into a more or less rigid state with the use of a pressure medium. Consequently, this guidewire unit needs a suitable pressure connection device for feeding the pressure medium into the guidewire unit and for discharging the pressure medium from the guidewire unit.
Especially in the field of medicine, so-called Luer lock connectors or rather Luer connectors are used to connect cannulae, syringes, infusion tubes, etc. to a supply source for a liquid or gaseous medium.
The invention is based on the technical problem of providing a pressure connection device, with which a guidewire unit of the conventional type, used for example, in medical instruments and which operates with a pressure medium, can be connected to a respective pressure medium source in an advantageous manner.
The invention solves this problem by providing a pressure connection device, which is intended for a guidewire unit operated with a pressure medium, in particular, for application in medical instruments, and which includes a connecting body, which accommodates a tube end section of a pressure medium tube of the guidewire unit. The connecting body has a pressure medium-controlled tube holding element, which in a pressurized state secures the tube end section in the connecting body in a fluid tight manner, and in a pressure relieved state releases the tube end section in order to detach from the connecting body.
The pressure connection device, comprises, in particular, a pressure medium-controlled tube holding element, which is provided on the connecting body, which accommodates a tube end section of a pressure medium tube of the guidewire unit. The tube holding element is configured so as to hold detachably the tube end section, so that in a pressurized state the tube holding element secures the tube end section in the connecting body in a fluid tight manner, and in a pressure relieved state the tube holding element releases the tube end section for removal from the connecting body. In this way, it is possible to achieve a detachable coupling of the guidewire unit, which is to be supplied with the pressure medium, to an associated pressure medium source in a manner that is advantageous from both a functional and production viewpoint. In the case under discussion, the term fluid is defined as both liquid and gaseous mediums. That is, the fluid tight seal provides protection against leaks from either liquid or gaseous pressure mediums, which are used as a function of the application.
In a further development of the invention, the tube holding element exhibits a holding/sealing diaphragm, which in the pressure relieved state allows an axial movement of the tube end section, which is accommodated in the connecting body, whereas in the pressurized state the holding/sealing diaphragm rests against the tube end in a securing and fluid tight manner. This feature constitutes a realization of the tube holding element that is advantageously simple and functionally reliable. In an advantageous embodiment of this technique, the holding/sealing diaphragm is designed as a sealing diaphragm sleeve, which in the pressure relieved state envelops the tube end section, which is accommodated in the connecting body, in such a manner that this tube end section can still perform an axial movement in and/or in relation to the sealing diaphragm sleeve. As an alternative, it is possible to design the holding/sealing diaphragm in other ways, for example, in the form of a holding diaphragm, which rests only locally against the tube end section, which is accommodated in the connecting body, without totally enveloping the tube end section in the circumferential direction.
In another embodiment of the invention, the tube holding element exhibits a pressure chamber, which can be filled with a pressure medium and on which the holding/sealing diaphragm abuts, so that the holding/sealing diaphragm can be switched between its state, in which it secures the tube end section, and its state, in which it releases the tube end section, by controlling the medium pressure in the pressure chamber.
In an advantageous further development of the invention, the tube holding element exhibits a pressure medium connecting element, which is configured in such a manner that it feeds the same pressure medium to the pressure chamber as to the pressure medium tube. Consequently, it is possible to use in a simple way the same pressure medium, for example, compressed air, which is needed in any event for the guidewire unit, in order to control the sealing diaphragm sleeve by way of the pressure chamber.
In an additional advantageous embodiment of the invention, the pressure medium connecting element exhibits a feed delay system, which is configured in such a manner that it feeds the pressure medium to the pressure medium tube so as to be delayed as compared to the pressure chamber. This feature guarantees that at an adequately early stage the sealing diaphragm sleeve already secures the tube end section in a fluid tight manner before the inlet area of the pressure medium tube exhibits a noticeable buildup in pressure owing to the delivered pressure medium. That is, the feed delay guarantees in an automatic way that at an adequately early stage the sealing diaphragm sleeve will be put into its pressurized state, which seals the accommodated tube end section, when the pressure medium is to be fed into the pressure medium tube. Thus, expensive pressure controlling mechanisms elsewhere are not absolutely necessary.
A variety of different variants may be considered in order to realize the feed delay system. Of these variants, two advantageous variants are provided as further developments of the invention. Thus, it is possible to realize the delayed feed of the pressure medium to the pressure medium tube as compared to the pressure chamber by running a pressure inlet, which can be connected to a pressure medium source, directly to the pressure chamber and by connecting an inlet area of the pressure medium tube to the pressure chamber by means of one passage aperture or a plurality of passage apertures in a corresponding partition. Therefore, the delivered pressure medium flows first and primarily into the pressure chamber and from there into the inlet area of the pressure medium tube and finally into the pressure medium tube itself, so that the sealing diaphragm sleeve has already moved with certainty into its sealing, pressurized state, before the inlet area of the pressure medium tube exhibits a buildup of any noticeable pressure of the pressure medium, which could lead to leaks in that area if the sealing diaphragm sleeve were not yet adequately pressurized. According to another variant, the delayed feed of the pressure medium to the pressure medium tube as compared to the pressure chamber is brought about by a cross section-reducing inlet nozzle, which is located downstream of a connection of the pressure medium inlet to the pressure chamber in the inlet area to the pressure medium tube. In this case, too, the pressure builds up first and primarily in the pressure chamber. As a result, the sealing diaphragm sleeve assumes its pressurized state, in which it secures the tube end section in a fluid tight manner, before any noticeable pressure has been built up in the inlet area of the pressure medium tube downstream of the inlet nozzle.
The pressure connection device comprises typically a return valve, which is mounted in the interior of the tube end section of the pressure medium tube of the guidewire unit and which opens in order to introduce the pressure medium into the pressure medium tube and closes in order to prevent the pressure medium from flowing out of the pressure medium tube. This feature automatically prevents the pressure medium from escaping from the pressure medium tube and, thus, from the guidewire unit, when the pressure medium has been fed beforehand to this guidewire unit, even if the guidewire unit with its pressure medium tube is detached from a pressure connection that is used eventually in order to connect to a corresponding pressure medium source. Mounting the return valve in the interior of the tube end section does not change the outer diameter of the respective tube end section and/or connecting area of the pressure medium tube and, thus, the guidewire unit in this area, so that the guidewire unit, which is provided with the return valve, can be used or rather can be manipulated without the return valve in the same way as an analogous conventional guidewire unit.
The technique of mounting the return valve in the tube end section of the pressure medium tube of the guidewire unit can be combined especially with the techniques with respect to attaching in a detachable manner the guidewire unit to a connecting body. In this case, the return valve makes sure that upon removal of the connecting body from a pressure medium source and/or upon removal of the guidewire unit from the connecting body, the pressure medium, which was fed beforehand into the guidewire unit, stays there.
In an advantageous embodiment of the invention, the return valve comprises a ball valve and one associated closing and opening stop each for said ball valve. Both the closing stop and the opening stop are fitted into the tube end section at an axial distance in such a manner that the ball valve can move adequately in the axial direction and in the pressurized state of the guidewire unit rests in a closing manner against the closing stop, whereas upon introduction of the pressure medium into the pressure medium tube, said ball valve leaves its closing position at the closing stop and moves in the direction of the opening stop. The opening stop exhibits a pressure medium passage aperture, which remains open even in the event that the ball valve is resting or pushing against said opening stop so that the pressure medium can flow into the pressure medium tube. In an advantageous embodiment, a return spring is braced against the opening stop. This return spring pushes the ball valve against the closing stop. Such a return spring is not absolutely mandatory, but it can facilitate the ball valve and, in addition, can control in a desired manner the feeding of the pressure medium through the choice of a suitable spring tension.
An additional embodiment of the invention provides a pressure relief pin in order to force open the return valve. To this end, the pressure relief pin exhibits an actuating mandrel, with which the ball valve can be moved away from its closing stop in the direction of the opening stop. In this way the pressure medium can be drained from the guidewire unit, and the guidewire unit can be moved into a less pressurized and/or pressure relieved state. In an advantageous embodiment, the pressure relief pin can be accommodated in a detachable or stationary manner in a receptacle of the connecting body, so that it does not have to be stored separately.
Advantageous embodiments of the invention are depicted in the drawings and are described below.